BURLEY, Idaho -- Fire officials believe it was spontaneous combustion that made a gun room explode at the home of an Idaho state lawmaker last weekend.

The blast sent Representative Fred Wood's wife to a burn center in Salt Lake City on Saturday night.

Burley Fire Chief Keith Martin believes a gun room below Fred and Amy Wood's house exploded after rags with gun cleaning chemicals on them sat in a garbage bin and slowly produced enough heat to ignite on fire.

He cleaned his guns, and we are thinking maybe the cleaning solvent and the rags that he used sat there over the week and slowly generated enough heat, where it finally spontaneously combusted, said Chief Martin.

” rags with gun cleaning chemicals on them sat in a garbage bin and slowly produced enough heat to ignite on fire.”

I’ve seen this happen with paint stripper rags left in a garbage can,,, by a complete doofus. But they didn’t explode, just caught on fire. Luckily, I had just opened the store as they burst into flame. Put it out immediately, before it could spread.

Let’s say a fire did start in a pile of improperly stored rags. OK, a small fire spreads and grows into a larger fire.

WHAT “Exploded”? The gunpowder in the plastic or metal tins? hmmmmmm.... I don’t think so. Bigger fire mostly likely.

What [generally] causes an explosion in a house fire? — generally vapors in an explosive mixture come in contact with a source of ignition [in a moderately confined space in the household] — and the fuel for the explosion is something like natural gas or gasoline vapors, or propane etc.

So **IF** there was an explosion, I have questions about what the FUEL was for this ‘explosion.’

REM: I *used* to be a volunteer firefighter MANY years ago.

Just being an inquiring mind in the face of today’s sloppy journalism.

I dunno. I still can’t get “explosion” from oily rags, gunpowder, primers, loaded rounds, etc. I could understand fire, but not explosion. Unless there was something in the room that I don’t normally keep.

I could go with that IF we knew what the Fire Chief identified as the explosive fuel and the source of ignition.

It takes a good bit of fuel evaporating to reach a lower explosive limit, unless of course the fuel is gasoline, propane or natural gas. solvents tend to make a brief flash fire and then a smaller Class A/B fire burns. They don’t often produce the high pressures of a gasoline vapor or propane/methane explosion. It just doesn’t read well.

I am really curious what the fuel REALLY was for this ‘explosion’. Spontaneously combusting rags do not an explosion make on their own.

The investigation is ongoing. I admit that the mechanism for the explosion is not clear. However, it appears that it was a pretty low level explosion, on the order of a propane or natural gas explosion. I say this because the (most likely) reinforced concrete cover for the safe room seems simply to have been lifted off, then fell back into the room. Here are some theories put forward thus far:

A room of stored ammunition and reloading supplies can hold enough explosive force to cause the damage seen in Burley, a local firearms expert said.

Safe rooms are often built very heavily, said Dan Hadley, reloading expert and employee at Reds Trading Post in Twin Falls. If a spark occurs, he said, that ignites the stored gunpowder and the room can become like a cartridge case with the pressure finding release at the weakest spot, which would be the roof.

When gunpowder ignites, he said, it creates an expanding gas.

In rooms with a lot of stored ammunition and reloading supplies it could easily blow a roof off, he said.

Sparks or heat can come from several different sources. Hadley said if gun cleaning and oiling supplies are kept in a room in a closed container, it can lead to the possibility of spontaneous combustion.

Something like that is more likely to happen in an auto repair shop where there are more rags, he said.

He said although cleaning and oiling supplies are volatile, they are safe if the directions are followed. Its always best to store them in a location separate from reloading supplies and ammunition, he advised.

Another source of ignition is some type of electrical short, Hadley said.

What you write is akin to a BLEVE — boiling liquid expanding vapor explosion. But in your write up the gas pressure is caused by the burning gunpowder which has its own oxidizer.

So essentially the ‘explosion’ was gas pressure — a burst if you will, of a pressure vessel— which introduced O2 to a combustible/explosive mixture (a back draft fire of sorts) and thus a ‘boom’ and only enough flame front to set her hair afire but not toast her.

I dunno. I still cant get explosion from oily rags, gunpowder, primers, loaded rounds, etc. I could understand fire, but not explosion. Unless there was something in the room that I dont normally keep.

Solvents evaporating, rags ignite, a small fire ensues. The door is opened, more oxygen is allowed into the room, a flash-over occurs. Not an explosion as such but close enough to a "low explosive" so as not to matter. A flash fire would also explain how the wife burned her face and hands.

Regards, GtG

23
posted on 10/02/2012 3:36:32 PM PDT
by Gandalf_The_Gray
(I live in my own little world, I like it 'cuz they know me here.)

Just read the complete story at the media web site. Flash fire only makes sense if someone opened the door. Given the injuries that would have had to have been the wife, he was not injured.

Something does not smell right, a small bottle of powder solvent is not going to blow down half a house and move a concrete patio slab. Wife was outdoors, he was inside when something very energetic let loose. Sounds like the fire marshal is busy shoveling "horse byproduct" over the unlikely event.

G

24
posted on 10/02/2012 3:46:26 PM PDT
by Gandalf_The_Gray
(I live in my own little world, I like it 'cuz they know me here.)

a small bottle of powder solvent is not going to blow down half a house and move a concrete patio slab.

Powder solvent is probably pretty close in energy density to gasoline. Dynamite has an energy density of about 7.5 MJ/kg. Gasoline has an energy density of 44.4 MJ/kg. So, pound for pound gasoline has more than 6 times the energy of dynamite. However, gasoline is not an explosive and dynamite is not a fuel, so they serve purposes that are mutually exclusive for the most part.

So, pound for pound gasoline has more than 6 times the energy of dynamite. However, gasoline is not an explosive and dynamite is not a fuel, so they serve purposes that are mutually exclusive for the most part.

If your car/truck engine ever "knocks" the gasoline is detonating as an explosive. Smooth combustion as a fuel is only a few degrees of spark timing away from explosive combustion. The nitroglycerin in dynamite is not detonated by burning thus if you don't mine the expense, you can burn dynamite in a nice cheery fire in a wood stove.

Under the right conditions flour, dust (grain, sawdust, coal), and finely divided metal particles as well as various hydrocarbon vapors can be made to explode (Ie: detonate where the flame front achieves transonic velocity).

In general vapor media must be evenly dispersed in a containing volume with enough oxygen to completely burn the vapor. Too rich (more vapor then O2) and the flame front will not achieve maximum velocity. Too lean (not enough vapor to react with the O2) and the flame front will extinguish prematurely. The correct mixture is referred to as the "stoichiometric mixture" and is dependent on the quantitative relationship between reactants and products so that all of the reactants are converted to end products with a maximum release of energy by the chemical reaction.

Dust explosions are not overly fussy about stoichiometric conditions and are therefore more likely to occur under everyday conditions such as a flour/grain mill or a coal mine. You can also use "dust" to greatly boost the power of a small bit of conventional explosive.

Regards, GtG

26
posted on 10/02/2012 6:06:14 PM PDT
by Gandalf_The_Gray
(I live in my own little world, I like it 'cuz they know me here.)

Disclaimer:
Opinions posted on Free Republic are those of the individual
posters and do not necessarily represent the opinion of Free Republic or its
management. All materials posted herein are protected by copyright law and the
exemption for fair use of copyrighted works.